1. Field of the Invention
The present invention relates to an information recording medium such as a DVD (Digital Video Disk) characterized by high-density recording and, more particularly, to a rewritable information recording medium. The present invention also relates to an information recording apparatus for recording information on such an information recording medium. The present invention also relates to an information playback apparatus for playing back information from such an information recording medium.
2. Description of the Related Art
In recent years, DVDs have been extensively studied. DVDs are roughly classified into read-only DVD-ROMs and rewritable DVD-RAMs. A DVD-RAM has a lead-in area, data area, and lead-out area. The data area has a user area where user data is recorded and a spare area which compensates for a defective area in the user area. For defect management, defect management tables in the lead-in and lead-out are used. On the basis of this defect management, a replacement process is executed. For example, Jpn. Pat. Appln. KOKAI Publication No. 11-185390 discloses a technique related to defect management.
The positions of defect management tables are permanently assigned for each format. The reliability of a table itself is increased by preparing a plurality of tables with identical contents. In this method, however, every time a defect occurs, all tables must be rewritten, resulting in access delay.